Cooling of high frequency vibrating means in combustion chambers



March 6, 1956 2,737,163

E. HUNDT COOLING OF HIGH FREQUENCY VIBRATING MEANS IN COMBUSTION CHAMBERS Filed Jan. 51, 1952 /m e// zar fiber/24rd. A an A42 United States Patent @r COOLING OF HIGH FREQUENCY VIBRATING MEANS EN COMBUSTEON CHAMBERS Eberhard Hnndt, Stuttgart, Germany, assignor to Daimler- Benz Aktiengesellschaft, Stuttgart-Untarturkheim, Germany Application January 31, 1952, Serial No. 269,155

Claims priority, applicatien Germany February 5, 1951 8 Claims. (Cl. 123-4131) It is, accordingly, an object of the present invention to increase the resistivity of the vibration generator against the high thermal and mechanical loads, so as to extend its useful life of service.

Accordingly, it is an essential characteristic of the present invention that the vibration transmitter, which transfers the vibrations to the fuel, is directly cooled by a cooling liquid. According to a further characteristic of the present invention, the vibration transmitter itself is set into vibrations by the vibration generator through the medium of a liquid, for example, the cooling liquid.

According to another characteristic of the present invention, a wall or a diaphragm is used as a vibration transmitter which is either arranged so as to be freely movable and which is made to vibrate through the medium of the liquid, or which may be appropriately supported by a grating structure or a similar supporting means. However, if desired, any other vibration transmitter may be used, such as, for instance, a metallic plate which is set into vibration through the medium of a liquid, for example, oil.

' By reason of the direct cooling action, the vibration transmitter may also be exposed to the very high temperatures in the combustion chamber. Moreover, by interposing, for example, a liquid between the vibration transmitter and the vibration generator, it is possible to avoid any transfer of heat from the vibration transmitter to the vibration generator.

Further objects and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows for purposes of illustration only several preferred embodiments of the present invention and wherein:

Figure 1 is a cross sectional view of a first embodiment utilizing a quartz crystal as vibration oscillating element.

Figure 2 is a further embodiment in accordance with the present invention utilizing electromagnetic means to produce the vibrations, and

Figure 3 is a still further embodiment in accordance with the present invention utilizing a metallic plate as vibration transmitter.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to Figure 1 thereof, reference numeral designates the cylinder head provided with the vibration transmitter, which is located above the combustion chamber 11 and between the valves. The vibration transmitter 12 is placed in an opening or recess of the combustion chamber 11 substantially in the center thereof. In the embodiment illustrated in Figure 1, a diaphragm 12 serves as a vibration transmitter. The diaphragm 12 is retained in its seat formed in the cylinder head 10 by means of a sleeve provided with openings 23.

The vibration transmitter may be set intooscillations of high frequencies, such as ultrasonic frequencies, by means of the vibration generator 15. A quartz crystal may be used as a vibration generator, which may be caused to oscillate by electric current of predetermined frequency which is conducted thereto by way of a bar 16 or in any other appropriate manner. The space 17 formed between the vibration generator 15 and the diaphragm 12 is filled with a cooling liquid, such as water, which is conducted into the space 17 from the cooling jacket 18 of the cylinder head 10 through openings 13. The cooling water may, for example, be made to flow in a continuous manner so that the vibrations produced by the vibration generator 15 are transferred to the diaphragm 12 by means of the cooling liquid contained in the space 17.

The fuel may be injected in any appropriate manner as, for example, laterally through a nozzle 19.

In the embodiment illustrated in Figure 2, the diaphragm 12, which operates as the vibration transmitter, supports itself against a grating network 15. The supporting grating network 15' consists, for example, of separate, interrupted supporting elements forming such network.

The bar or shaft 16 is caused to oscillate by the electromagnetic coil 20 which is energized in any well-known manner. The oscillations produced thereby are there upon transferred to diaphragm 12 by means of the supporting grating network 15'. It is, therefore, best to use frequencies up to 20 kc. for this purpose. The frequency should be chosen so high that the mixture no longer exhibits any compressible characteristics at these frequencies, i. e., the pressure of the sound waves is transmitted with supersonic speed. However, on the other hand, they should be chosen relatively low, having in mind the desired effect of disintegration on the little fuel drops. The transmission of the vibrations from the grating network 15' to the diaphragm 12 may take place directly, whereby diaphragm 12 oscillates in a direction away from the grating network to one side only. However, the space 1 7 may also be filled with air or gas, or a liquid as will best serve the purpose of the construction. The liquid for use in the space 17' may be permitted to flow out from the space 18 forming the cooling jacket of the cylinder head. The diaphragm together with the grating network 15 is kept in its position by a cover 14'.

In the embodiment illustrated in Figure 3, a metallic plate, such as, for example, a brass plate 12' is used as a vibration transmitter. The brass plate 12' is set into oscillations emitted by the vibration generator 15" by means of a liquid in the space 17" such as, for instance, oil. The vibration generator 15" may be in'the form of a quartz plate.

In this embodiment, the fuel is injected through an annular nozzle, or through several nozzles annularly disposed in front of the vibration transmitter 12'. The fuel may be injected against the vibration transmitter 12 or may be injected in a direction parallel to the surface thereof.

The high frequency vibrations or oscillations may be produced in any suitable manner, as by means of a quartz crystal or a magnetostrictive supersonic wave generator, of which the latter is less sensitive to heat and which permits a simple design. i

The fuel may be admitted or injected into the combustion chamber as a fuel mixture or as a liquid. The fuel may be admitted already at the beginning of the compression stroke, i. e., without the presence of any counterpressure. Consequently, a quantitatively apportioned admission or injection of the fuel is required which is thereupon atomized just prior to completion of the com pression stroke. The minute fuel drops of molecular size. thusprodueed. are. moved through the entire combustion chamber at a high speed so that simultaneously with the automatic whirling action an easily ignitable, quickly combustible mixtureis produced; in this manneiga very rapi'dcombustion' is made possible with loads ofl relativelylow compression.

While I have-:shown severalspecific embodiments in accordance with the present invention, it is not intended that the same beilimited thereto, except as set forth in the appended claims,. but rather be construed to inciude all such changes andmodifications as are obvious to a person skilled'in the art. For example, powdered fuels may be substituted for the. liquid fuels, and supporting grating networks .may bezusedin any or all of the above-described embodiments.

\Vhattl claim. is:

l. Inaninternal combustion engine a cylinder having a piston therein, a combustion space, means for feeding fuel to said combustion space, means exposed. to said combustion space for producing high-frequency sound vibrations, and a cooling space outside of said combuslionspacewitha cooling medium therein, said cooling space directly limiting said last-named means and directly cooling the same.

2. in an internal combustion engine a cylinder having a piston therein, a combustion space provided with a recess, means for feeding fuel into said combustion space, a member located in said recess and forming part of the walls of said combustion space, one side of saidmember being exposed tosaid combustion chamber a member located in said recess and forming part of the Walls of said combustion space, one side of said member being exposed to said combustion chamber and the other side there of lying outside of said combustion chamber, means for setting said member into vibrations at high frequencies to thereby produce high frequency acoustic vibrations, and direct cooling means including a cooling agent for said member, said member being exposed on the one side to said combustion space and on the other side to said cooling. agent.

4. In an internal combustion engine a cylinder having a piston therein, a, combustion space provided with a recess, means for feeding fuel into said combustion space, a member located'in said recess and forming part of the walls of said combustion space, one side of said member being exposedto said combustion chamber and the other side thereof lying outside of said combustion chamber, means for setting said member into vibrations athigh frequencies to thereby produce high frequency acoustic vibrations, and a cooling space outside of said combustion space with a cooling medium therein, said cooling space directly limiting said last-named means, said lastnamed means including a supporting grate for supporting saidme'mber to be set into oscillations by high frequency vibrations, one side of said grate abutting the vibrating surface of said member.

5. In an internal combustion engine a cylinder having a piston therein, a combustion space provided with a recess, means for feeding fuel into said combustion space, a member located in said recess and forming part of the walls of said combustion space, one side of said member being exposed to said combustion chamber and the other side thereof lying outside of said combustion chamber, means for vibrating said member With high frequency acoustic vibrations and direct cooling means including a cooling agent for said member, said second-named means including a vibration transmitter located at, a distance from said member outside of said combustion chamber, the space between said vibration transmitter and said member forming a cooling chamber, and cooling means in said cooling chamber.

6. in an internal combustion engine a cylinder having a piston therein, a combustion space provided with a recess, means for feeding fuel into said combustion space, a member located in said recess and forming part of the walls of said combustion space, one side of said member being exposed to said combustion chamber and the other side thereof lying outside of said combustion chamber, means for vibrating said member with high frequency acoustic vibrations, and direct cooling means including.

a cooling agent for said member, said second-mentioned means including a supporting grate for supporting said member to be set into oscillations by high frequency vibrations, and said direct cooling means including the cooling chamber located on the side of said member opposite said combustion space, and means for filling said cooling. chamber formed between said vibrating means and said element with said cooling agent.

7. In an internal combustion engine, a cylinder block with a cylinder and a piston sliding therein and defining a combustion chamber in the top dead center thereof, a cooling jacket space in said cylinder block adapted to conduct a cooling liquid through the cylinder block for purposes of cooling thereof, an element located in the wall of said cylinder block delimiting said combustion chamber, means for oscillating said element at high fre quencies whereby the oscillations are transferred from said member to the medium in said combustion chamber, a space forming a cooling chamber provided on the side of said element opposite said combustion chamber, walls for said last-named space, and passage means between said last-named space and said cooling jacket space whereby the cooling liquid is directly conducted along the back of said element.

8. in an internal combustion engine the combination according to claim 7, in which the said element is designed as a diaphragm combined with a plurality of separate supporting elements on the cooling side of said first-named element, adapted to absorb the pressures coming from the combustion chamber, which act on the diaphragm.

References 'Cited in the file of this patent UNITED STATES PATENTS 2,040,652 Gaty May 12, 1936 2,142,466 Wagner Jan. 3, 1939 2,414,494 Vang Jan. 21, 1947 2,436,570 Hancock Feb. 24, 1948 2,453,595 Rosenthal Nov. 9, 1948 FOREIGN PATENTS 487,032 Germany Nov. 30, 1929 

